32
2.2.2.
Preliminary
settings
As the following
settings
are
identical
for both vertical
channels,
only
the procedure
for channel
A has been
indicated.
Unless
otherwise
stated, the
controls
occupy
the
same
position
as in the
previous
adjusting
procedure.
2.2.2.
1. Adjusting
the
gain
—
Operate
push-button
A of the
display-mode
controls
(SI
)
—
Operate
push-button
A of the trigger
-mode
selector switch
(S22)
—
Operate push-button
AUTO
of the trigger-mode
controls
(S8)
—
Operate push-button
MAIN
TB
of the horizontal
deflection controls
(S2)
-
Display
the
trace by
means
of
the
A POSITION control
—
Set the INTENSity
and FOCUS
controls for
a
sharp,
well-defined trace
The controls
not mentioned
may occupy
any position.
—
Set the channel
A
AC-O-DC switch
to DC
—
Set the channel
A AMPLitude
switch to 0.5 V and the continuous
control
to
CALibrated
—
Connect the
CALibration
socket to the A input socket.
—
Check
that the
trace height
is exactly 6 divisions.
If
necessary,
readjust the GAIN
control on the front panel, immediately
below the AMPLitude switch.
2.2.3. Inputs
A and B and
their possibilities
The oscilloscope has
been provided
with two identical channels, each of which can be used
for
either YT
measurements in
combination with
one or both time-base generators, or XY measurements
in combination
with the external horizontal
channel.
2.2.3.
1.
YT
measurements
To display
one signal, one of the
two
vertical channels
can be selected
by
operating
either push-button
A
or
push-button
B of the vertical
display-mode
controls.
When push-button
ALT
or
CHOP
is depressed,
two
different
signals
can be displayed simultaneously.
The
Y
deflection coefficient
and the polarity can
be
selected
for
each channel individually. When
the ALT
button
is operated, the display is switched
over from one channel
to
the other
at
the flyback
of
the
time-base
signal.
Although
the ALTERNATE
mode can
be
used
at
all
sweep speeds of
the time-base
generator, the
CHOPPED
mode will give
a better display quality for long sweep times, because during these long
sweep times
the
alternate display
of the two input signals is clearly visible
to
the
eye.
In
the CHOPPED mode,
the
display
is switched over from one
channel
to
the other
at a
fixed
frequency.
If push-button ADD
of the display mode switch is operated, the signal voltages of both vertical channels
are added. Depending
on the positions of the polarity switches, either the sum or the difference of the
input
signals is displayed. The ADDED
mode also enables differential measurements. With these measurements
advantage is taken from the common
mode rejection
in
the
ADDED
position.
When
the polarity switches of
both channels
are set
to
opposite positions, the common mode parts of the signals on sockets A and
B will
undergo
a
very
slight amplification only, with
respect to
the differential mode parts.
2.2.3.2.
XY
measurements
If push-button EXT
X
DEFL
of
the horizontal display-mode selection controls
and
one of the TRIG
OR X DEFL
controls are operated, the time-base generator are switched off. If for example push button A
of
S22
is depressed,
a
signal
applied
to
the vertical A channel is then used for horizontal deflection. The
AC/O/DC switch
and the step attenuator of channel A remain operative. Horizontal trace shift is possible with
the X POSITION
control and continuous control
of
the deflection coefficients with
the A
AMPL/DIV control.
Vertical channel B
may also be used for X deflection.
To
this end, the B
button of the TRIG OR X DEFL controls is depressed.
It
is
also
possible to use
an
internal
voltage at the
mains
frequency or
a
signal applied
to
the EXT
socket at
the bottom
right-hand
side of the front panel
for X
deflection,
after depressing the relevant push-button of
the TRIG OR X DEFL
controls.
In the EXT
and
EXT
-;
10 modes the trace width can be controlled
with the
X-AMPL/HOLD
OFF
potentiometer.
With this
potentiometer in its CAL
position, the deflection
coefficient for external signals
is
50
mV/DIV.
The external
signal
can be either d.c.
or a.c.
coupled
(lower frequency limit
7 Hz) by depressing
either the
DC
or the
LF
push-button
of the
trigger coupling controls
of the main time-base.
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